Intake and Exhaust Systems

Question 1

intake system parts

Answer 1

air silencer, air cleaner and Screen, air box or header, air heater, air cooler, blower, intake valves or ports

Question 2

intake system function

Answer 2

supplies air for combustion, cleans the air and reduces the noise created by the air as it enters the engine

Question 3

naturally aspirated intake

Answer 3

only on four stroke engines. Air and fuel mixture is forced into cylinders by the vacuum caused by piston movement. The Venturi effect is the principal where air drawn through a narrow valve opening is accelerated as it passes through and the passage widens, then a vacuum occurs

Question 4

blower

Answer 4

increases flow of air into cylinders by compressing it and forcing it into an air box or manifold

Question 5

Scavenging

Answer 5

the process of pushing exhausted gas-charge out of the cylinder and drawing in a fresh draught of air or fuel/air mixture for the next cycle

in two stroke engine Scavenging takes place during the latter part of the downstroke and in the early part of the upstroke

in a 4-stroke engine Scavenging takes place when the Piston is nearing and passing top dead center during the latter part of an upstroke in the early part of a Down stroke

Question 6

supercharging

Answer 6

supplies more compressed air into the combustion space than can be supplied through atmosphere pressure, piston action, or Scavenging. powered by engine output

Question 7

two-stroke engine supercharging

Answer 7

occurs after exhaust valves are closed

Question 8

four stroke engine supercharging

Answer 8

intake and exhaust valve have extreme overlap and a blower is added to the intake system

Question 9

silencer

Answer 9

quiet air coming into intake system. There are three types: dry, viscous, and oil bath

Question 10

dry type silencer

Answer 10

cleans and silences by drawing air through a screen

Question 11

viscous type silencer

Answer 11

draws air through mesh or screen which is viscous or what usually with a medium weight oil. maybe made of cotton, wire, copper, or metal wool

Question 12

oil bath type silencer

Answer 12

incoming air is forced vertically downward into oil reservoir. Once reached the air changes Direction rapidly and is forced back up to engine intake system. The dirt is trapped in the reservoir

Question 13

air intake system wear and fail

Answer 13

dust, plugged air filter, coolant to air leaks in after cooler, hydraulic lock

Question 14

air cleaner

Answer 14

removes foreign matter from air and passes required volume of air for proper combustion and Scavenging

Question 15

light-duty, oil wetted air cleaner

Answer 15

a metal screen that is saturated with oil and supported in side a cylindrical housing

Question 16

light-duty, oil bath air cleaner

Answer 16

a wire screen inside cylindrical housing which contains and oil bath below the element. after air is forced through the bath it is directed upwards by baffles

Question 17

air cleaner maintenance procedures

Answer 17

keep air cleaner type on air intake pipe

keep air cleaner properly assembled so joints are strictly oil tight and air tight

immediately repair any damage to air cleaner or related parts

inspect and clean or replace the air cleaner element as operating conditions warrant

after servicing the air cleaner, remove air Inlet housing and clean accumulated dirt deposits from blower screen and the inlet housing

carefully inspect the entire air system periodically

Question 18

Roots type blower

Answer 18

uses positive displacement, a fixed volume of air moved with every rotation of rotors.

compression process is external to the blower. As volume of air present in intake manifold increases relative to actual volume of intake manifold, the air pressure increases

Question 19

screw type blower

Answer 19

realize on internal compression. Pulls air through meshing lobes that resemble worm gears. air in side is trapped In Pockets and compression builds as the pocket size decreases

Question 20

centrifugal type blower (turbocharger)

Answer 20

driven through a gear Train by the engine crankshaft, it takes power from the exhaust gases. The gases from the exhaust manifold drive a turbine which drives and impeller on the same shaft

Question 21

crankcase ventilation importance

Answer 21

prevents water vapor from condensing so corrosion and contamination is lessened. prevents fuel dilution and water contamination. prevents ignition in a hot spot within engine caused by lubricating oil

Question 22

crankcase ventilation

Answer 22

passageways called Breather System. conducts intake air to the cylinders from the cleaning, silencing, and compression areas.

in two stroke engine may be called an air block or an air header

in four stroke engine may be called a manifold

Question 23

exhaust system

Answer 23

carries gases away from cylinders, muffles exhaust noise, quenches Sparks, removes solid material from exhaust gases, furnishes energy to turbocharger

Question 24

exhaust manifold

Answer 24

passageway for gases to leave after combustion and discharge from cylinder space

the exhaust manifold is made up of sections called chamber assemblies along with expansion joints and
adapter assemblies.

Question 25

pyrometer

Answer 25

indicates exhaust temperature by measuring the difference between the electric current produced by heat acting on dissimilar Metals in the thermocouple hot Junction and the cold Junction